1. Field of the Invention
This invention relates to heat storage systems and has particular reference to devices for measuring and indicating the amount of heat energy remaining at any time in a heat storage unit.
2. Description of the Prior Art
The utilization of solar energy to provide heat for heating water, space and the like is becoming increasingly popular. Although substantial amounts of heat energy can be obtained through this medium, it cannot be obtained in a continuous manner but is dependent upon weather conditions, time of day, etc. Therefore, heat storage media, such as water, rocks beds, etc., are usually provided to store a certain amount of the heat transferred from a solar heat collecting device and to expend the same when called for. Often, when the heat remaining in such storage unit becomes depleted because it is used up faster than it can be furnished by the collector device, conventional heat sources are called upon to replenish the same in the storage unit.
Heretofore, temperature sensing devices, such as thermometers, were generally used in an attempt to determine the amount of heat energy contained in a heat storage unit at any time. However, such devices do not give a meaningful indication of the amount of usable heat obtainable from the storage unit. Thus, for example, a solar energy user may have a bath turn cold, poorly cleaned laundry or his home be inadequately heated because he lacked an understandable heat storage monitoring system which would permit him to tailor his activities to the heat energy available at a certain time in the heat storage unit. On the other hand, the user may unduly restrict usage of heat energy remaining in the heat storage unit for fear of depleting such heat energy before his various energy demands are taken care of.
It is therefore a principal object of the present invention to provide a device for computing and indicating the relative usable heat energy existing in a heat storage unit.
Another object of the invention is to provide a device of the above type which continuously computes and displays the percentage of usable heat energy between predetermined upper and lower temperature limits.
Another object is to provide a device of the above type in which the predetermined acceptable upper and lower temperature limits may be readily changed as desired.
Another object is to provide a device of the above type which embodies a minimum number of parts.
A further object is to provide a device of the above type which is easy to install, light, compact, rugged, aesthetically pleasing, and inexpensive to produce.